What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
Please refer to our user guide: How-to-prevent-emails-landing-in-spam-folder-in-your-Gmail-account
It should be applicable as well even for non gmail email service.
To make sure also that your email service will not block the submission email, you can also setup the Notification email to use your own SMTP email.
Hope this help. Let us know if issue persist.